Apparatus for forming sealing beads on removable paper closures for containers



y 0, 1956 o. J. LINDROTH ETAL 2,753,767

OR FORMING SEALING BEADS ON REMOVABLE PAPER CLOSUREJS FOR CONTAINERS APPARATUS F 2 Sheets-Sheet 1 Filed Jan. 31, 1955 OSCAR J. LINDROTH 0nd JOHN G. KEMPE INVENTORS ATTORNE July 10, 1956 o. J. LINDROTH ETAL APPARATUS FOR FORMING SEALING BEADS ON REMOVABLE PAPER CLOSURES FOR CONTAINERS 2 Sheets-Sheet 2 Filed Jan. 51, 1955 OSCAR J. LINDROTH 0nd JOHN G. KEMPE INVENTORS ATTORNEY United States Patent 2,753,767 APPARATUS FOR FORMING SEALING BEADS ON REMOVABLE PAPER CLOSURES FOR CON- TAINERS Application January 31, 1955, Serial No. 485,042

3 Claims. (Cl. 93-1.3)

This invention relates to an apparatus for forming a peripheral sealing head on a removable paper closure for a container. More particularly, the invention relates to an improvement in the manufacture of paper closures of the cover-all cap type for use on paper tub or cup containers, which improvement resides in forming a laterally projecting, peripheral bead on the cap for sealing engage ment with the usual internal annular sealing groove of a conventional paper tub.

The primary object of the invention is to provide a paper closure with a peripheral sealing bead which will precisely fit into, and firmly engage with, the annular sealing groove of a container.

Further objects are to form said head accurately and precisely so that both the diameter and thickness of the bead may be held to precise dimensions in each closure made.

A still further object is to form said bead in a plane slightly below the plane of the bottom of the closure so that the closure may be more readily removed and replaced in the annular sealing groove of the container.

Other objects and advantages of the invention will be apparent from the following description taken in conjunction with the accompanying drawings, in which:

Figure 1 is a bottom plan View of a closure made according to the present invention;

Figure 2 is a side elevation thereof;

Figure 3 is an enlarged fragmentary sectional view thereof on the line 33 of Figure 1 and shown in engagement with a container;

Figure 4 is a perspective view of a machine for forming beads on closures according to the present invention;

Figure 5 is an enlarged longitudinal sectional view of a portion of the machine of Figure 4; and

Figure 6 is an enlarged fragmentary sectional view, similar to Figure 3, of a partially finished closure prior to having the bead formed according to the invention, the finished bead being indicated in broken lines.

Referring more particularly to Figures 1 and 2, the closure 10 has a substantially plane, circular bottom portion or disk 11, a substantially vertical side Wall 12, and a protective flange or collar 13 terminating in a depending skirt 14. A peripheral sealing ring or head 15 is located at the juncture of the disk 11 and side wall 12, and projects laterally beyond the side wall 12 while lying in considerable part below the disk 11. The closure 10 is of the general type shown in United States Patent No. 1,101,687 issued June 30, 1914, to C. C. Deeds, except for the addition of the conventional skirt 14.

In Figure 3, the closure 10 is shown in place on a laminated paper tub 16 of conventional construction, the sealing bead 15 being seated in the annular sealing groove 17 of the tub.

In Figure 6, the closure 10 is shown in full lines in partially finished condition as formed in conventional shaping dies similar to those described in United States Patent No. 1,575,300 issued March 2, 1926, to Wallace M.

Weeks and John A. Pease. In this partially finished conice dition, the paper stock that ultimately forms the sealing bead 15 constitutes a depending fold 18 at the lower end of the side wall 12, The depending fold 18 does not project laterally beyond the side wall 12, but is formed by the bottom 11 being pressed up within the side wall 12, and hence the fold 18 projects below the bottom 11.

It will be understood by those familar with the art that, in order to form the side wall 12 and the protective collar 13 to the precise dimensions desired, a portion of the lower face of the upper die must project down to the bottom 11 within the side wall 12. Similarly, a portion of the upper face of the lower die must project up around the side wall 12 within the protective collar 13. Side wall 12, during its formation, is therefore supported on either side by vertical faces of the upper and lower dies, and, at this stage, cannot have any laterally projecting bead at its lower end.

Laterally projecting beads on container closures have heretofore been formed by withdrawing the lateral sup port of the vertical face of the lower die and squashing the side wall down to force part of the side wall laterally into the space afforded by withdrawal of the vertical wall of the lower die. Closures with beads formed in this manner have not been entirely satisfactory due to the dilficulty of holding the bead to the precise dimensions desired and the difficulty of ejecting the cap from the die without distortion.

The present invention comprises a separate spinning or rolling operation on closure 10' in apparatus hereinafter described to displace the depending fold 18 to form the laterally projecting head 15 as shown in broken lines in Figure 6. It will be understood that directions herein mentioned, unless otherwise indicated, are with reference to the closure 10 as shown in Figure 2, upward being in the direction toward the top thereof and lateral being from the center thereof toward the sides.

Referring to Figures 4 and 5, a retainer plate 20 having a male die surface onto which the top of the partially finished closure 10' precisely fits, is secured by screws, or otherwise, to the face plate 21 of an ordinary lathe or lathe-like machine 22. Coaxially with retainer plate 20, a roller device 23 is non-rotatably mounted in the tailstock 24 of lathe 22 by means of a conventional taper shank 25.

At the forward end of shank 25 is an integral, cupshaped, spring housing 26 having a peripheral flange 27 to which is bolted an outer housing 28. Within the spring housing 26, a heavy coil spring 29 is compressed against the enlarged end or piston 30 of a pressure housing 31. This piston 30 is normally held against the shoulder 32 of the outer housing 28 by spring 29, but is free to travel axially of the device 23 a substantial distance to the shoulder 33 of the spring housing 26 when spring 29 is further compressed.

The other end of pressure housing 31 is tubular and the reduced neck 34 of the rotating pressure plate 35 is journalled for rotation therein by means of sleeve bearing 36. An end thrust bearing 37 is located between neck 34 and piston 30, and permits rotation of plate 35 despite the end thrust exerted against its neck 34 by spring 29 and piston 30. The pressure plate 35 has a fiat surface 38 at its forward end which is adapted to fit within the depending fold 18 of the closure 10 and to clamp the bottom 11 of the closure against the retainer plate 20.

It will be understood that the pressure plate 35 may be moved away from retainer plate 2!) by moving the tailstock 24 in conventional manner. A partially finished closure 10 may then be inserted in the device over the die surface of the retainer plate 20 and will be clamped thereon by moving the tailstock toward the face plate 21 until the pressure plate 35 engages the bottom 3 11 of the closure. Moving tailstock 24 still farther toward the face plate 21, will move the outer housing 28 toward retainer plate 20 and toward pressure plate 35, this movement being permitted by compression of spring 29 until piston 33 strikes stop shoulder 33.

On diametrically opposite sides of the outer housing 28, the end rollers 40 are r'otatably secured by shoulder screws 41 to the housing 28. A bushing'42 provides a bearing surface for rotation of the rollers and a spacer 43 positions each roller 49 so that the inner fiat face thereof is substantially tangent to pressure plate 35 but just out of contact therewith. Rollers 40 have a-reduced circumferential surface 44 adapted to contactxthe dependingfold 18 and a flange portion 45 spaced from the axis of :the device 23 a distance-which is equal to one-half the desired diameter of the finished head forreasons which will hereinafter become apparent.

The shoulder screws'41 have a reduced threaded portion which is screwed into a hole in the outer housing 28 radial to the axis thereof. The screws 41 arelocated close tothe end of housing28-so that aportion of each roller Atiprojects beyond the housing on either side of pressureplate 35 toward the retainerplate 30. The distance thatrollers 46 project beyond housing 28 is such that, whenpiston 30 is in contactwith shoulder 32 and a closure 10' is clamped between pressure plate '35 and retainer plate 20, as shown in Figure 5, the curved surfaces 44 of rollers 40 contactdepending-fold 18.

A side roller 46 is mounted with its axis parallel to that of the device 23 and perpendicular to the axes of rollers 40 by means of a shoulder screw 47, bushe'd at 48, which is secured to an arm 49 fixed, inconventional manner, to the toolpost 50 of the lathe 22. The roller 46 is cut awayas shown to provide clearance for the rollers 40 and to form a narrow flange 51 having a peripheral surface and a lower surface-52. The lower surface 52 is located immediately at the desired location of the upper edge of the bead 15. The side roller 46 is secured in the toolpost 50 so that it may be moved into and out of contact with the side wall 12 of the closure 10 between the skirt 14 and flange 45 of the end rollers 40. It will be evident that the skirt :14 of the cap 10 must be short enough to permit the entrance of the flange 51 beneath the skin.

The operation of the roller device 23 will be apparent from the foregoing. A partially finished closure 10 is inserted, manually or otherwise, over the die portion of the retainer plate when the tailstock is backed away from the retainer plate. The tailstock 24, carrying the device 23, is then advanced toward the retainer plate until the pressure plate 35 contacts the bottom 11 of the closure 10 which is then held flat between retainer plate and pressure plate. The toolpost 50 is then moved toward the device 23 until the flange- 51-of the side roller 46'is firmly'pressed against the vertical side Wall 12.

The lathe 22 is then started and'the face plate 21 and retainer plate 20 revolve. Closure 10, in position on retainer plate 20 and with the flat face 38 of pressure plate 35 pressing bottom 11 of the cap against retainer plate 20, also revolves. Pressure plate 35likewise' turns, and the bearing 36 turns with it within the pressure housing 31. the depending fold 18 of the cap 10, causing the rollers 40 to rotate about the screws 41 as the cap is turned.

The side roller 46, being pressed against the side wall 12 of the closure, is also rotated about the screw 47,-

The surfaces 44 of the end rollers 40 contact ward. While this operation is taking place, the outward movement of the paper stock is confined by the inner surface of flange 45 of the rollers 40, thus defining the outer diameter of finished bead 15. Any tendency of the side wall 12 to bulge or crumple under the end pressure exerted by rollers 41) is resisted by the side roller 46, which compresses the side wall 12 against the side of retainer plate 20, thus continuously pressing the side wall 12 during the rolling operation. At the same time, the lower surface 52 of side roller 46 corrects any excessive upward movement of the bead .15 and accurately defines the upper edge of the bead. v The bead thus assumes the position indicated at 15 in broken lines in Figure 6 and the finished closure 10 is formed. The tailstock 24 and toolpost 50 andassociated parts are again backed away from retainer plate 20 and the finished closure 10 is removed.

It will be apparent that the outside diameter of bead 15 is precisely limited by the distance between flanges 45.of the rollers 40. Similarly, the thickness of bead 15 is determined by the distance that rollers 40 are moved toward retainer plate 20 and this distance may be precisely determined by the location of the shoulder 33. The location of bead 15 with relation to the bottom 11 of the finished cap is, of course, determined by the position of the side roller 46 and the distance that the end rollers 40 are advanced toward the retainer plate 20. The thickness of head 15 is determined by the spacing between rollers 40 and roller 46 as the tailstock 24 is moved to its final position nearest to face plate 21.

It .willbe evident that each finished closure 10, produced by the above-described method of rolling, will have a head 15 with dimensions precisely the same so that a tight seal may be produced with the groove 17 of the tub 16. Since head 15 lies in aplane slightly below that of the bottom 11, however, there is a slight flexibility in the head which allows closure 10 to be easily, appliedto the tub 16 and easily removed without substantially permanent deformation of the bead 15.

While the device 23 in the drawings shows only two end rollers 40, it will be apparent that three or more rollers 40 may'equally well be used. Only one side roller 46 is shown in the drawings, but a plurality of side rollers may also be used.

It will also be apparent that the same result might be obtained by an arrangement of parts in which the rollers 40 and 46 revolve about the longitudinal axis of the device 23'while the closure 10 is held stationary. Since rollers '40 must be advanced toward the retainer plate 20, however, while the roller 46 does not advance, the arrangement of parts showninthe drawings is considered the least complicated.

The head rolling or spinning apparatus of Figure 5 has been described, and shown in Figure 4, as mounted in a conventional bench lathe in order that the description might be more easily understood. However, it will be understood that the apparatus of Figure 5 is'preferably made part of an automatic machine-in which the steps of loading the partially finished cap, forming the head 15} and discharging the finished cap, take place automatically and more quickly than would be possible by manual operationl While there is herein described, and in the drawings shown, an illustrative embodiment of the invention, it is to be understood that the invention is not limited thereto, but may comprehend other constructions, arrangement of parts, details. and feature'sjwithout departing from the spirit of the invention. We desire to be limited, therefore, only by the scope of the appended claims.

We claim:

1. An apparatus for forming" a laterally projecting,

peripheral sealing beadon'a pape'r cap closure fo'rl containe'r s', saidclosure'having' a circular bottomportion, a substantially cylindrical side' wall and ajp'rotective collar atthe upper end 'ofsaid wall, and said bottom portion be ing pressed up within said side wall to form a depending fold of paper stock at the lower end of said side wall, comprising, in combination, closure supporting means adapted to fit within the top of said closure, roller supporting means mounted coaxially therewith, said supporting means being relatively movable axially of one another and one of said supporting means being rotatable, means rotatably mounted in said roller supporting means and coaxial therewith for clamping the bottom portion of said closure to said closure supporting means, a plurality of end rollers mounted rotatably on and having their axes located radially with respect to said roller supporting means, each end roller having a peripheral surface adapted to contact said depending fold and roll it upward and laterally outward with respect to the side wall of said closure, at least one side roller rotatably mounted with its axis at right angles to the axes of said end rollers and with its periphery in position to engage said side wall of the closure below said collar and immediately above said fold, said side roller being adapted to compress the side wall of said closure laterally against said closure supporting means and to define the upper edge of said peripheral bead, means for rotating the rotatable one of said supporting means, and means for axially advancing and retracting said supporting means relative to one another.

2. An apparatus as set forth in claim 1 in which each of said end rollers is provided with a flange exterior to and projecting radially beyond its fold-contacting peripheral surface for limiting the lateral projection of said peripheral bead.

3. An apparatus for forming a laterally projecting, peripheral sealing bead on a paper cap closure for containers, said closure having a circular bottom portion, a substantially cylindrical side wall and a protective collar at the upper end of said wall, and said bottom portion being pressed up within said side wall to form a depending fold of paper stock at the lower end of said side wall, comprising, in combination, closure supporting means adapted to fit within the top of said closure, means for rotating said closure supporting means, roller supporting means mounted coaxially with said closure supporting means and axially movable with respect thereto, resilient means rotatably mounted in said roller supporting means and coaxial therewith for clamping the bottom portion of said closure to said closure supporting means, a plurality of end rollers mounted rotatably on and having their axes located radially with respect to said roller supporting means, each end ro'ller having a peripheral surface adapted to contact said depending fold and roll it upward and laterally outward with respect to the side wall of said closure and having a flange exterior to and projecting radially beyond said peripheral surface for limiting the lateral projection of said rolled fold, at least one side roller rotatably mounted with its axis at right angles to the axes of said end rollers and with its periphery in position to engage said side wall of the closure below said collar and immediately above said fold, said side roller being adapted to compress the side wall of said closure laterally against said closure supporting means and to define the upper edge of said peripheral bead, means for axially advancing and retracting said roller supporting means relative to said closure supporting means, and means for moving said side roller into and out of engagement with the closure side wall.

References Cited in the file of this patent UNITED STATES PATENTS 822,068 Moxham May 29, 1906 2,250,799 Harrison July 29, 1941 2,595,046 Amberg Apr. 29, 1952 

